The invention relates to a gathering device for raising and lowering a gathered curtain, which has gathering rollers distributed over the horizontal length of the curtain. These gathering rollers are provided with pull elements that can be wound up for raising and lowering the gathered curtain and are rotatable by a common drive element about their roller axles.
A device for raising and lowering a gathered curtain is known from German Offenlegungsschrift No. 33 05 300. This device comprises gathering rollers spaced apart from one another, distributed over the horizontal length of the curtain. The gathering rollers are secured via bearing blocks, for instance on a curtain rail. The axles of the gathering rollers extend in the longitudinal direction of the curtain or curtain rail. All the rollers are disposed such that they are secured against relative rotation on a winding shaft that is supported in the bearing blocks and is extended to one to one longitudinal end of the curtain. Located on one longitudinal end of the curtain is a wind-up roller, the axle of which is in alignment with the winding shaft. The wind-up roller may for instance be equipped with a cord, preferably a cord having spaced ball like elements secured thereto. The cord hangs downward from the wind-up roller into an area that is within reach of the person manipulating the curtain. This kind of wind-up device, comprising the wind-up roller and the cord, can also be replaced with a drive motor that acts directly upon the wind-up roller.
A device of this kind entails extraordinarily high engineering effort, and it is also heavy in weight. Sturdy securing means are needed and it has to be installed with very good alignment, to prevent the wind-up shaft from sticking in the bearings of the bearing blocks. Even so, such expensive devices are sluggish in operation. A particular disadvantage is that with the known design, only a single curtain layer can be gathered.